Sexually transmitted infections

Last updated: October 20, 2023

Summarytoggle arrow icon

The term "sexually transmitted infections" (STIs) refers to a group of infections that are mainly transmitted via sexual intercourse. The most common symptoms of STIs are pain in the suprapubic and genital area, urethral or vaginal discharge, and genital lesions, which may or may not be painful. Some STIs (e.g., HPV) may induce or predispose to malignant changes. The majority of STIs are asymptomatic, and therefore easily spread. If a patient is already infected with an STI, they are predisposed to coinfections with further STIs. There are various treatment options for each STI, with simultaneous treatment of the partner often necessary to prevent recurrent infections. In some cases, health care providers are required by law to report cases of STIs to county and health state departments (e.g., HIV, hepatitis B).

Overview of sexually transmitted infectionstoggle arrow icon

Overview of sexually transmitted infections


Associated disease Management
Viral pathogens
Human papillomavirus type 6 and 11

Herpes simplex virus type 2 (HSV-2)

  • Acyclovir PO for episodic or suppressive treatment
Hepatitis B virus (HBV)
Bacterial pathogens
Chlamydia trachomatis D–K
Chlamydia trachomatis L1–L3
Klebsiella granulomatis
Haemophilus ducreyi
Neisseria gonorrhea
Treponema pallidum
Parasitic pathogens
Trichomonas vaginalis
Phthirus pubis

Management of sexual partnerstoggle arrow icon

The following applies to patients diagnosed with a bacterial STI or trichomoniasis; patients with viral STIs (herpes simplex, HPV, HIV, hepatitis B, hepatitis C) need to take lifelong precautions. See the respective articles for more information.

  • Contact tracing of all sexual partners within the last 60 days (even if asymptomatic)
  • Expedited partner therapy: the treatment of sexual partners of patients who have been diagnosed with STIs by giving prescriptions to the index patients
  • Avoid unprotected sex until all of the following criteria are met:
    • Completion of 7-day treatment regimen OR 7 days have passed since a single-dose treatment.
    • All symptoms have resolved.
    • Any current sexual partners have also met the above criteria.
  • Prevent STIs in patients and partners: See “Prevention” below.
  • Retest individuals to check for reinfection.

Sexual partners must be treated simultaneously to avoid reinfections.

Preventiontoggle arrow icon

Genital lesionstoggle arrow icon

Overview of genital lesions
Pathogen Clinical features Diagnosis
Painless lesions
Human papillomavirus type 6 and 11
Klebsiella granulomatis
Chlamydia trachomatis L1–L3
Treponema pallidum
Painful lesions
Herpes simplex virus type 1 and 2 (mostly HSV-2)
Haemophilus ducreyi
  • Clinical exam and culture

Trichomonas vaginalis

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Referencestoggle arrow icon

  1. 2015 Sexually Transmitted Diseases Treatment Guidelines: Gonococcal Infections. Updated: July 27, 2016. Accessed: March 25, 2017.
  2. Guidance on the Use of Expedited Partner Therapy in the Treatment of Gonorrhea. Updated: March 1, 2021. Accessed: March 9, 2021.
  3. Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR. Recommendations and Reports. 2021; 70 (4): p.1-187.doi: 10.15585/mmwr.rr7004a1 . | Open in Read by QxMD
  4. Legal Status of Expedited Partner Therapy (EPT). . Accessed: April 11, 2022.
  5. Molina J-M, Charreau I, Chidiac C, et al. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label randomised substudy of the ANRS IPERGAY trial. Lancet Infect Dis. 2018; 18 (3): p.308-317.doi: 10.1016/s1473-3099(17)30725-9 . | Open in Read by QxMD

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